Oil platforms are often used in offshore oil and gas production. In the operation of offshore oil platforms, it may be necessary to install electronic equipment under water (e.g., for controlling functions of a subsea Christmas tree or a subsea blowout preventer). More recently, subsea processing facilities have been established in which processing equipment, such as electrically driven pumps and gas compressors, are relocated to the ocean floor. Subsea processing facilities may be provided with a power grid as well as control, monitoring, and communication systems.
In both of these examples, a subsea installation is provided at the ocean floor. The subsea installation comprises electronic equipment that may be monitored and/or controlled from a topside installation, which may comprise a topside control system and which may be based on a marine vessel (e.g., a ship or a platform), or may be based onshore. The subsea installation may, for example, comprise a Well Control Module (WCM) or a Manifold Control Module (MCM) that may receive commands from the topside installation or that may transmit information to the topside installation.
In a conventional system, the communication between the topside control system and such module of the subsea installation is generally based on the AFSK (Audio Frequency Shift Keying) modem standard, such as Bell 202. By using a Bell 202 modem at the topside control system and another Bell 202 modem at the subsea installation that is connected to the respective subsea module, a data transfer rate of about 1200 Baud at half duplex may be achieved. If several Bell 202 subsea modems are connected to the topside modem, a data transfer rate of 1200 Baud divided by the number of subsea modems may be achieved for each subsea modem. The data transfer is thus rather slow and may not easily be upgraded.
There is an increased demand for monitoring and controlling subsea installations, which requires higher bandwidth for transferring the data of sensors and/or control signals between the subsea and the topside installations. Updating the existing infrastructure (e.g., modems of the subsea control modules and data lines in the umbilical), may be a cost intensive process.